Steam turbine



K. BAUMANN.

STEAM TURBIN E.

APPlIcATloN FILED QcT 2. 1920.

Patented 1m31, 1922.

UNITED srarssrATaNr OFFICE.

' KARL naman-NN, on IIRMsToN, nNeLANnnssIGNoRQTo THE nnITIsI-rwnszrine ,4 nonsn ELECTRIC AND MANUFACTURING Coi/IPANY ',IiIIvIIIEn, 'A COMPANYl 'or 'GREAT BRITAIN. y

ysriiiiiw: TURBINE.

Y 1920. sriai Np.414,3o1. Y l

To all -wwm imag/concern 1 Be 'itknown that I, KARL BAUMANN, Vva citizen of the Confederation. ofy Switzerland,

' and a resident of Urmsto'n, in the'county of Lancaster, England, have inventedk a newand useful Improvement in Steam Turbines, which is a division of application SerialNo. 232,571, lfiled May il, 1918, of which the following is a specication. p I `v l This invention relates to steam turbines of the axial flow type. i

Oner of the limiting factors which determines the out-put of steam turbines of a given. speed and eiiiciencyis the maximum permissible length ofthe moving blades in the low pressure stages. In order that the length of the low pressure blades mayV be kept within vpermissible limits, the low pressure portion of a turbine is sometimes `constructe-d as a multiple stage, one portion of the steam only acting in parallel in each sec-` tion of the multiple stage,r and 4 flowing through adjacent sections thereof inV oppo-A site directions. v

VvIt has also been proposed to construct turbines in which the steam flowing in substantially the same directionl throughout 'a low pressure part, of the turbine .isy segregated into annularv portions, which are ex# panded at the same vor different-rates and pass from a vplurality of rows of moving blades to the exhaust. l

According to the present invention, one portion of the steam leaving an intermediate stage flows through a; segmental part of the next succeeding row or rows of stationary" guide blades and cooperating moving blades andthence tothe exhaust. The remaining portion of the steam leaving the intermediate stage passes through a second segmental part ofsaid next succeeding row or rows of blading, during which passage a small part only 'of lits energy is transformed orA 'abstracted, and then vflows in substantially the same axial direction through va further row or rows of stationary guide blades and co"- operating moving'blades and thence to the exhaust. v y j i Y j Steam turbines 1in accordance with'this invention'may be constructed in a variety of Y ways, one of which g is illustrated by way of example in accompanying drawings in which.

E ig. 1 isa central, longitudinal Sectional view, of the steam turbine, all@ Fig@ S a cross sectional view taken on linev II-II-fof F ig. 1. A I v Y Referring nowjto Figs. 1 and 2, the tur Specification-of LettersPatent. Patlentedpgan', 3K1,- 1922, original application ined Maya 191s, serial Nb. 232,571'. Divided and this appnqaiiqn mea octoterf2,

bine cylinder is indicated at 13 and the shaft i at V14,''the'turbi'ne here illustratedbeinglof the impulse type.'v The steam is 'admittedxto a nozzle box 15 and thenceto a plurali-ty of rows of stationary nozzles;` 16, 16a, 16H-etc., and moving blades 17 17a, 17.*?, etc., respectively cooperating therewith, each of thesta- .tionary blades and cooperating moving ing provided with the stationary guide'V blades V32for the passage of steamV through the upper segmental portion ofthe moving blades 20. From the radial edges 21of'the upper portion of the vdiaphragm 19 a divi'- sion wall ordiaiphragm 22 extends within the exhaust ycasing 23 downwards, as shown,

to the exhaust outlet of the turbine' 243; The diaphragm 22 has a saddle-shaped surfaceMH and forms a guide` for that portion 'of kthe Vsteam leaving the movingblades 17f which passes through the stationary blades 18 and the moving blades 2O to theexhaust outlet a Y Vdoes not pass through theseginental set ofN i guide `blades 18, is directed through the sta;

tionary blades 32 and the upper segmental portion of the moving blades 20 on its wayV to the final row ofstationary guidev blades 26. As the `upper segmental portion of this stage is intended toV passsteam from the portion ofthe row ofmovingblades 17 f. to the final row 'ofstation'ary blades 26 and .co4 operating blades 27 ,the guide blades 32 are .so designed .that the drop in pressure of rthe steam passingacross them is assmall l as possible. Accordingly the guide blades 32are designed 'with'a large'exit angleso as to pass the' maximum,quantityl of steam for a i-given area of drop'v in'p'ressur'e, and atA the Sametime-,diraiireiiamtarnetareehih suitable shape to give the desired diifuserl leaving the upper portion of the moving blades 20. Said diffuser may conveniently consist of a row of stationary blades 33 of effect. y

1" The turbine may either be so designed that: practically no mechanical work is obtained from'the upper portion. of the mov- 1 ing blades 20, or be so designed. that a proportion of vthe energy is abstracted from the steam'passing through the upper portion of the moving blades 20, the remaining energy of said steam' being abstracted by the moving blades 27. Alternatively, the turbine may be designed in such a way that energy is imparted to the steam whilst flowing' through said upper portion of the moving blades 20.

Preferably, though not necessarily, the

exhaust casing enclosed below the-diaphragm- 22 and the rear portion of the exhaust casing which receives the steam from the final row of movingblades 27 are provided with' internal guide walls such as'28, 29, 3() of the kind described either in the specification of patent application, Serial No.' 123,697 filed the 4th October 1916 or oi patent applica` tion,-Serial No. 187,963 filed the 24th August 1917.

While I have shown my invention in but one. form, it will be obvious to those skilled i.

in the artthat it is not so limited, but is susceptible of various other changes and modifications without departingifroinf theV spirit thereof, and I desire, therefore, that only such limitations shall lieplaced thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is z# l. In an elastic-iiuic tn -bine in which tl e vl elastic fluid' is diviced into two segmenta o ort-ions and expanded at differ-ent rates for cooperation with row of moving blades and means for expanding the leastexpanded ortion vvfor cooperation with another row ofblades.- Y 2. In anA elasticdiuid tl'lrhine, a row .of moving blades, means cooperating with said row to secure the division of elastic fluid passing therethrough into segmental portions anda greater degree of energy-abrstraction from one portion than from the other, another row ofl moving blades, and means for admitting said' portion of elastic fluidi. which khas undergone the lesser degree of energy-abstractionto the latter row of blades for further energy-abstractiong charged 3. In a turbine, la section comprising a plurality of rows of moving blades, means for segm entally dividing the elastic fluid passing through one row of blades into a plurality of portions and for leading one of the portions to another row of blades, and fixed guide blades for the first row of moving blades, those for the portion of the elastic fluid subsequently admitted tothe otherl row of moving blades having large outlet angles.`

4L. In an elastic-fluid turbine, a section comprising a pluralityof rows of moving blades, fixed guide blades for admitting elastic fiuid to one Vof said rows of moving blades, means cooperating with said row for dividing the elastic iiuid discharged therefrom into a plurality of segmental portions and for conducting one of the portions for full-peripheral admission to another row ofv blades. Y n f 5; In an elasticdiuid turbine, a section comprising a row of moving blades,1neans cooperating with said row of blades 'for dividing the elastic fluid passing therethrough into a pluralityof segmental portions, fixed guide blades for admitting elastic fluid to said row of blades, another row of moving blades, and means for conducting one of said segmental portions of elastic fluid for admission to the last-named row of blades.

6. In an elastic-fluid turbine, a low-pressure section comprising a plurality of rowsl of moving blades, fixed guide blades for admitting elastic fluid to one of said rows of moving blades, and means cooperating with said row for dividing the elasticfluid discharged' therefrom into a plurality of segmental portions9 leading one of the segmental portionsY tothe exhaust, andr leading another segmentalportion for admission to another row of moving blades. y

y7. In an elastic-fluid turbine, a l0w-presY sure section comprising a fixed diaphragm, segmental rows of guide'blades carried by said liaphragm, one row having relatively large outlet angl s, i adapted `.to receive elastic fluid from said guide blades, means cooperating with the, moving blades to segregate the elasticflnid discharged. thereinto by said row of blades 'large outlet angles frein that disby'the other row, and another row of moving blades adapted to receive elastic fluid which haspassed throughsaid row having large outlet angles.

ilo

a -row of moving blades 8. Ina steam turbine of the axial iow type, means for passing a portion only of the steam leaving an intermediate stage through a segmental partV of the next succeedingrow vor rows of stationary guide blades and cooperatingfmoving blades, and Y tioned segmental part being designed vto con- Y vert a different proportion ofthe pressure yenergy of the steam flowing through theml into velocity energy than the guide blades of the second mentioned segmental part.

9. In a steam turbine of theaxial flow type, means for passing a portion only of the steam leaving an intermediate stage through a segmental part ofthe' next succeeding row or rows of stationary guide blades and cooperating moving blades and thence to exhaust, and means for passing the remaining portion of the steam through a second segmental part of the said next succeeding row or rows of blading and through a further row or rows of stationary guide blades and cooperating moving. blades and thence to exhaust, said stationary guide blades of the first segmental part being designed to convert a greater'proportion of the pressure energy of the steam flowing through them into velocity energy than the guide blades of the second mentionedsegmental part. 25'

10.7In a steam turbine of the axial 'How type, means for directing all offthe steam through intermediate stages,` and'directing a portion only of the steam througha *seg-V mental part of the next succeeding rowA oftionary guidevblades and cooperating moving blades and thence tol exhaust, means for passing the remalningporti'on of the steam through a second segmental part of said next succeeding row or rows' of blading and a through a further row or rows of stationary guide blades and cooperating moving blades and thence to exhaust,V randmeans comprising a diffuser for partly reconverting; into pressure energy the velocity energy of the Vsteam leaving the second .mentioned 'segf' mental part before it passes to the saidfurther row or rows of blades. f

12. In a steam turbine `of the axial flow typefmeans forpassing a portion onlyI 0ftheV steam'V leaving anv intermediate ystage through a segmental part of the next succeeding row or rows of stationary guide blades and cooperating moving blades .and thence to exhaust, and means'for passingfthe remaining portion of the steam through a second segmental part of the said next suc.- Y

`ceeding row or rows of blading and then through a further row or rows of stationary guide blades and cooperating moving blades and thence to exhaust, said stationary guide blades of the first segmental part being designed to convert a greater proportion of the pressure energy of the steam flowing v. through them into velocity energy than thel guide blades of the second mentioned seg-V mental part, and means comprising a diffuser p for partly reconverting into pressure energy the velocity energy of the steamv leaving the second mentioned segmental part before it passes to the said further row or rowsl of blades.'

In testimony whereof I have ber, 179270. l y

' f 'KARL' BAUMANNQ- A `hereunto subscribed my name this 28 day of Septem- 

